The present invention relates to a method of identifying a plant species, especially rice and lawn glass, with pyrolysis-gas chromatography.
Recently, food safety consciousness, farm product brand certification, and consumer gourmet trend have been spreading, so that a selection criterion for farm products has been focused. Main selection criteria include a production location and a species to be clearly marked on a farm product. For example, identification of rice such as a cultivar, a production location, and a production year are required to be clearly marked on a package material under Japanese Staple Food Control Act. In the near future, such a requirement may be enforced to other farm products of all plants such as lawn glasses and flowers, in addition to rice.
In view of the background, it has been desired to develop new technology for determining a species scientifically, precisely, simply, and rapidly at low cost. In conventional technology, a morphological method, a color of leaf, a grain shape of a fruit tree, and polymorphism of enzyme expression (isozyme pattern) have been used for identifying a species of a farm product or plant. However, it is difficult to analyze cultivar or a similar species. Alternatively, a random amplified polymorphic DNA method (RAPD) has been developed (refer to Japanese Patent Application No. 2001-95589). In the RAPD method, a DNA is extracted from a sample, and the DNA is grown under a suitable random primer with the PCR method. Then, a molecular weight of the DNA is determined with electrophoresis.
In the RAPD method, it is necessary to grow DNA multiple times with the PCR method according to types of primers, thereby making the process complicated, taking long time, and increasing cost. There are many other common bands exist in addition to bands for identification. Accordingly, it is necessary to mix a large number of primers, thereby making it difficult to grow DNA with the PCR method. Among the bands for identification selected from multiple DNA bands, some of them are susceptible to an amplification reaction temperature and a DNA density, thereby causing a repeatability problem.
In view of the problems described above, an object of the present invention is to provide a method of determining a species of a plant rapidly and precisely at low cost without any special morphological method. Especially, when the method of the invention is applied to rice and lawn glass requiring a high quality brand, it is possible to determine a species with simple handling and high reliability at low cost.
Further objects and advantages of the invention will be apparent from the following description of the invention.